glance-registry fails to start

I followed the intallation guide on CentOS 6.2 and finished glance installation.

When use glance index command. I got the error like
Failed to show index. Got error:
The request returned 500 Internal Server Error

The response body:
Traceback (most recent call last):
  File "/usr/lib/python2.6/site-packages/eventlet/wsgi.py", line 336, in handle_one_response
    result = self.application(self.environ, start_response)
  File "/usr/lib/python2.6/site-packages/WebOb-1.0.8-py2.6.egg/webob/dec.py", line 147, in __call__
    resp = self.call_func(req, *args, **self.kwargs)
  File "/usr/lib/python2.6/site-packages/WebOb-1.0.8-py2.6.egg/webob/dec.py", line 208, in call_func
    return self.func(req, *args, **kwargs)
  File "/usr/lib/python2.6/site-packages/glance/common/wsgi.py", line 284, in __call__
    response = req.get_response(self.application)
  File "/usr/lib/python2.6/site-packages/WebOb-1.0.8-py2.6.egg/webob/request.py", line 1053, in get_response
    application, catch_exc_info=False)
  File "/usr/lib/python2.6/site-packages/WebOb-1.0.8-py2.6.egg/webob/request.py", line 1022, in call_application
    app_iter = application(self.environ, start_response)
  File "/usr/lib/python2.6/site-packages/keystone/middleware/auth_token.py", line 176, in __call__
    return self.app(env, start_response)
  File "/usr/lib/python2.6/site-packages/WebOb-1.0.8-py2.6.egg/webob/dec.py", line 147, in __call__
    resp = self.call_func(req, *args, **self.kwargs)
  File "/usr/lib/python2.6/site-packages/WebOb-1.0.8-py2.6.egg/webob/dec.py", line 208, in call_func
    return self.func(req, *args, **kwargs)
  File "/usr/lib/python2.6/site-packages/glance/common/wsgi.py", line 284, in __call__
    response = req.get_response(self.application)
  File "/usr/lib/python2.6/site-packages/WebOb-1.0.8-py2.6.egg/webob/request.py", line 1053, in get_response
    application, catch_exc_info=False)
  File "/usr/lib/python2.6/site-packages/WebOb-1.0.8-py2.6.egg/webob/request.py", line 1022, in call_application
    app_iter = application(self.environ, start_response)
  File "/usr/lib/python2.6/site-packages/WebOb-1.0.8-py2.6.egg/webob/dec.py", line 159, in __call__
    return resp(environ, start_response)
  File "/usr/lib/python2.6/site-packages/Routes-1.12.3-py2.6.egg/routes/middleware.py", line 131, in __call__
    response = self.app(environ, start_response)
  File "/usr/lib/python2.6/site-packages/WebOb-1.0.8-py2.6.egg/webob/dec.py", line 159, in __call__
    return resp(environ, start_response)
  File "/usr/lib/python2.6/site-packages/WebOb-1.0.8-py2.6.egg/webob/dec.py", line 147, in __call__
    resp = self.call_func(req, *args, **self.kwargs)
  File "/usr/lib/python2.6/site-packages/WebOb-1.0.8-py2.6.egg/webob/dec.py", line 208, in call_func
    return self.func(req, *args, **kwargs)
  File "/usr/lib/python2.6/site-packages/glance/common/wsgi.py", line 482, in __call__
    request, **action_args)
  File "/usr/lib/python2.6/site-packages/glance/common/wsgi.py", line 499, in dispatch
    return method(*args, **kwargs)
  File "/usr/lib/python2.6/site-packages/glance/api/v1/images.py", line 134, in index
    images = registry.get_images_list(req.context, **params)
  File "/usr/lib/python2.6/site-packages/glance/registry/__init__.py", line 129, in get_images_list
    return c.get_images(**kwargs)
  File "/usr/lib/python2.6/site-packages/glance/registry/client.py", line 77, in get_images
    res = self.do_request("GET", "/images", params=params)
  File "/usr/lib/python2.6/site-packages/glance/common/client.py", line 58, in wrapped
    return func(self, *args, **kwargs)
  File "/usr/lib/python2.6/site-packages/glance/common/client.py", line 420, in do_request
    headers=headers)
  File "/usr/lib/python2.6/site-packages/glance/common/client.py", line 75, in wrapped
    return func(self, method, url, body, headers)
  File "/usr/lib/python2.6/site-packages/glance/common/client.py", line 562, in _do_request
    raise exception.ClientConnectionError(e)
ClientConnectionError: There was an error connecting to a server
Details: [Errno 111] ECONNREFUSED

And actually my openstack-glance-registry service wasn't running.
openstack-glance-registry dead but pid file exists

And it's strange that the registry.log and api.log have no message for that. In fact the logs upgraded only when the database had been created.

I tried the command below after delete the tables in database glance but failed again.
glance-manage version_control 0
glance-manage db_sync

I also recreated the glance service in keystone, however, nothing happened. The glance-registry cannot start.

Please help~